is a loaded term. The IRA were terrorists to some, and freedom fighters for others. However one can perhaps describe a method of attack as terrorist without taking sides in conflict - chiefly one which involves an indiscriminate attack on civilians, or an attack on a military target with no regard for the likelihood of even greater civilian casualties. By that definition the bombings of Hiroshima, Nagasaki, and Dresden were terrorist attacks, regardless of your view on the justification of the WW2 in general.

The purpose of a terrorist attack is often not to achieve a military objective, but to, quite literally, strike terror into a general civilian population, with a view to cowing or suppressing them as a potential source of opposition, regardless of their own individual sympathies. Many civilians are simply caught up in an attack by being in the wrong place at the wrong time.

It is, and always should be, a war crime. But of course only the losers are ever prosecuted. The US could simply have demonstrated their military superiority by detonating a nuclear bomb over the sea within sight of Tokyo accompanied by an ultimatum to surrender. Dresden was simply an act of revenge. Much of modern day middle eastern originating terrorism is an inchoate response to the overwhelming military power of the US and Israel which makes any conventional response impossible to sustain.

The problem with terrorism is that it destroys both those it is directed at and those who use it - as the rise of Trump and the degradation of US political culture so eloquently testifies. The failure to prosecute Bush/Cheney and their acolytes for the Iraq war is the proximate cause - as is the ongoing failure to recognise the international court of Justice in Den Haag. American exceptionalism is breeding a terrorist monstrosity simply because there is no means of regulating the beast. Will we have to wait for the US to be defeated in a nuclear exchange for that to change? I hope not.

"Terrorism" is a conclusory term designed to conceal, not reveal. It is a label slapped on violent (and often on nonviolent) opposition by the current authorities to demonize that opposition and avoid having to recognize, let alone address, the issues giving rise to it.